"We know that the dark matter explanation is a long shot, but the payoff would be huge if we're right," study lead author Esra Bulbul, of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, said in a statement. "So we're going to keep testing this interpretation and see where it takes us."

Scientists believe that about 85 percent of matter in the universe is dark matter, which neither absorbs nor emits light, making it difficult to detect. Forbes reported the X-ray signals were observed coming from the Perseus galaxy cluster, which includes thousands of galaxies.

“We have a lot of work to do before we can claim, with any confidence, that we’ve found sterile neutrinos,” Maxim Markevitch, a co-author from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said in the statement. “But just the possibility of finding them has us very excited.”